Shockproof electromagnet with armature



Oct. 12, 1948. P. J. REIFSCHNEIDER SHQCKPROOF ELEGTROHAGNET WITHARIATURE Filed Jan. 26, 1948 r 5 MHZ mm TRIP J/IAF T 0'' CIRCUIT QREHKERInventcir: Paul .J. Rei'Fschneiden,

'His Attcbney.

Patented on. 12, fess UNITED mm PATENT OFFICE Paul J. Reihchncider,Springfield, Pa anignor to General Electric Company, a corporation of 3Application January 26, 1948,, Serial No. 4,403

My invention reiatesto improvements in electromagnetic devices and moreparticularly to improvements in electromagnetic devices for directlytripping circuit breakers.

An object of my invention is to provide a com-v pact, simple andeconomical electromagnetic device. Another object of my invention is toprovide for circuit breakers an improved direct trip electromagneticdevice which is so effectively shockproof as to avoid false trippingactions in cases of shock and the like. These and other objects of myinvention will appear in more detail wention with the tripping armatureshown in the attracted or tripping position; Fig 2 is a rear elevation,with a part of the mounting frame and a part associated with thearmature broken away, of the embodiment of my invention shown in Fig. 1;and Fig. 3 is a partial view similar-to Fig, 1 showing the armature inthe fully retracted position.

In the illustrated embodiment of my invention, I have shown anelectromagnetic tripping device comprising'a generally U-shaped core Iof suitable magnetic material. The core is provided with an energizingwinding 2 and a cooperating armature 3. As shown, the core i is mountedon a channel-shaped supporting frame 4 by suitable fastening means suchas bolts 5. These pass through the web 6 of the frame 4 into T-shapedslots I in the leg 8 of the core I and engage nuts 9. The core i and thearmature 3 are shown laminated since such a structure is desirable foruse with either alternating or direct current, the laminations beingheld together by suitable means such as rivets i and ii in the core andarmature respectively. Also, the end of the leg II of the core i and theend of armature 'l are shown with stepped pole faces so that a shortcircuit-ins or shading winding, not shown, may be conveniently placedabout the higher or projecting portion l3 of the core to reduce chatteras is well-known to the art. Alternatively, a steel ring may be placedabout the portion iii to reduce the air gap between the vertical facesof the poles thereby increasing the magnetic force at the open air-gapposition of the arms- 4 Claims. (Cl. 175-338) 2 L- ture. as iswell-known to the art. An anchoring strip I4 is used to hold the coil 2in place on the core leg ii, the lower flange I! being bent over afterassembly.

In accordance with my invention, the armature 3 has a pivotal edge l8which, in the illustrated embodiment of my invention, is formed by theintersection of the substantially plane end and side surfaces i1 and i8respectively of the armature. Also in accordance with my invention, Iprovide means'mounting the pivotal edge i8 of the armature 3 adjacentone end of the core i for angular movement of the armature toward andaway from the other end of the core. As shown, this means-comprises, atthe free end of the core leg 8, two intersecting substantially planesurfaces i9 and 20 forming a notch within which the pivotal edge i6 ofthe armature 3 is seated substantially coincidently with the line ofintersection of the plane surfaces i9 and 20 of the a notch. As shown,the angle between the end and side surfaces i1 and i8 of the armature issubstantially 90, whereas the angle between the plane surfaces is and 2cforming the notch is greater than 90 by a predetermined amountsuillcient to permit the desired angular movement of the armature 3 toand from the attracted position shown 'in Fig. 1.

For moving the armature 3 away from the attracted position which, in theilllustrated embodiment ofmy invention, happens to be at the end of thetripping movement, I provide suitable preferably resilient energystoring means such as ,a spring 2i which is suitably connected betweenthe web 8 of the frame 4 and a tripping arm or projection 22 mounted onthe armature. As shown, the tripping arm 22 is so arranged relatively tothe trip lever 23 on the trip shaft 24 of a circuit breaker that, uponmovement of the armature to the attracted position, the trip lever isturned counterclockwise to effect a similar movement of the trip shaftwhereby to release the tripping mechanism, not shown, of the circuitbreaker; For easing the end of the counterclockwise movement of thearmature 3 away from the attracted position, I provide a resilient stopsuch as a leaf spring element 25 which, as shown, is mounted on theinside of the frame 4 near the top thereof and on an inturned flange 28.In the unattracted position of the armature, this spring element alsoprevents bouncing of the armature on the occurrence of shocks.

It will be apparent that the spring 2i has a vertical or upwardcomponent of force which tends to lift the armature 3 bodily out of itspivotal support by moving the pivotally supported edge It upwardly alongthe notch face It. Such movement cannot, or course, be tolerated lesttripping arm 22 not strike trip lever 23. In accordance with myinvention, I provide means for preventing this movement whether due tothe spring 21 or to shocks and the like As shown, this means includes onthe armature 3 an arm iii which can be an extension of arm 32 and whichhas a portion 28 of substantially circular configuration with itscenteroi curvature in the pivotal edge It of the armature and of anangular extent at least equal to the desired angular movement of thearmature. The upward motion preventing means further includes a blockingmember such as a transverse rod 23 positioned adiacent the notchintersection substantially directly above the intersection of surfacesi9 and and, as shown, extending transversely of the frame d between thesides thereof. Also, the rod 29 has on itslower side a confining surface30 in engagement with the circular configuration 28 of the arm2T'whereby to prevent upward movement of the pivoted end thereof underthe verti= :al component of force of the spring 2i.

Further in accordance-with my inventionil provide means for preventingmovement of the armature 3 along the face 20 of the notch in consequenceof shocks and the like. As shown, this means comprises a stop elementsuch as the web 6 of the frame 4 and a cooperating pro- Jection 31 on anextension 32 of the arm 27 proexpensive and shockproof pivotal mountingfor the armature of an electromagnetic device which is particularlyadapted for tripping circuit breakers on war craft and the like whereall apparatus on board may be subjected to violent shock conditions.

While i have shown and described my inven- 7 tion in considerabledetail, I do not desire to be limited to the exact arrangements shown,but seek to cover in the appended claims all those modifications thatfall within the true spirit and scope of my invention.

What "I claim as new and desire to secure by Letters Patent of theUnited States is:

1. In an electromagnetic device comprising a generally U-shaped core, anenergizing winding. and an armature having a pivotal edge at one end,means mounting the pivotal edge of the armature adjacent one end of thecore for angular movement of the armature toward and away from the otherend of the'core comprising two intersecting plane surfaces on'the oneend of the core forming a notch within which the pivotal edge of thearmature is seated substantially coincidently with the line ofintersection of the plane surfaces of the notch, resilient mean tendingto turn the armature away from the other end of the core and having aforce component tending to move the pivotally supported edge of thearmature out of said notch, and means for preventing such movement ofthe armature including an arm onithe armature having a portion ofcircular configuration with its center in the pivotal edge of the armand of an angular extent at least equal to the angular movement'of thearmature, and a blocking member positioned adjacent the notchintersection and having a confining surface in engagement with thecircular configuration of said arm durmounted on the extension 32 of thearm 27 to Assuming the parts positioned as shown in Fig. 2 with thearmature 3 away from the at- ;tracted position against its cushionedstop 25 where it is held by the spring 2l, then, if the winding 2 isenergized by current sufllcient to attract the armature, clockwisemovement thereof to the attracted position actuates the trip lever 23 ina counter-clockwise direction to release the circuit breaker trippingmechanism. not shown. During the movement of the armature 3 in theclockwise direction as well as in the reverse direction, the curvedsurface 28 on the arm 21 rides along the bottom 3!)- of the stop 29whereby to maintain the pivotal edge It of the armature 3 coincidentwith the intersection of the notch faces i8 and 13. Also, any shockhaving a downwardly directed force component tending to lift the pivotaled e of the armature 3 out of the notch will be inefiective to do sobecause 01 the stop 29. The armature 3, however, will always be free tomove about its pivotal edge l6.

In case of shocks or the like having a force component from the left,the armature will tend to remain more firmly seated in its pivotalnotch. Shocks with a force component from the right will be ineffectiveto displace the pivotal end of the armature to the right by virtue of)the projection 3| on the arm2l engaging the web 6 of the frame 4.

In short, I have provided a sturdy, simple, in-

balance the armature 3 about the pivotal edge ing the angular movementor the armature.

2, In an electromagnetic device comprising a generally U-shaped core, anenergizing winding, and an armature having a plane end surface and aplane, side surface intersecting at an angle of substantially 90 degreesto form apivotal edge at one end, means mounting the pivotal edge ofcore, a spring tending to turn the armature away from the other end ofthe core and having a force component tending to move the pivotallysupported edge of the armature out or said notch,

and means for preventing such movement of the armature including an armon the armature having a portion of circular configuration with itscenter in the pivotal edge of the armature and of an angular extent at,least equal to the angular movement of the armature, and a blockingmember positioned adjacent the notch intersection and having a confiningsurface in engagement with the circular configuration of said arm duringthe angular movement of the armature.

substantially degrees to form a pivotal edge at one end, means mountingthe pivotal edge of notch within which the pivotal edge of the armatureis seated substantially coincidently with the line of intersection ofthe plane surfaces of the notch, a spring tending to turn the armatureaway from the other end of the core and having a force component tendingto move the pivotally supported edge of the armature along one of thei"aces of said notch, means for preventing such movement of the armatureincluding an'arm on the armature having a portion of circularconfiguration with its center in the pivotal edge of the armature and ofan angular extent at least equal to the angular movement of thearmature, and a blocking member positioned adjacent the notchintersection and having a confining surface in engagement with thecircular configuration of said arm during the angular movement of thearmature, and means for preventing movement of the armature along theother face of said notch in consequence of shocks and the likecomprising a sto element and a projection on said arm engageable withsaid stop element.

4. In an electromagnetic device comprising a generally iJ-shaped core,an energizing winding,

and an armature having a pivotal edge at one end, means mounting thepivotal edge of thearmature adjacent one end of the core for angu= larmovement of the armature toward and away irom the other end of the corecomprising two intersecting plane surfaces on the one end of the coreforming a notch within which the pivotal edge of the armature is seatedsubstantially coincidently with the line of intersection of the planesurfaces of the notch, resilient means tending to turn the armature awayfrom the other end of the core and having a force component tending tomove the pivotally supported edge of the armature along one of the facesof said notch,

means for preventing such movement of the armature including an arm onthe armature having a portion of circular configuration with its centerin the pivotal edge of the armature and of an angular extent at leastequal to the angular movement of the armature, and a blocking memberpositioned adjacent the notch intersection and having a confiningsurface in engagement with the circular configuration of saidarm duringthe angular movement of the armature, and means for preventing movementof the armature along the other face of said notch in consequence ofshocks and the like comprising a stop element and a projection on saidarm engageable with said stop element.

' PAUL J. REIFSCHNEIDER.

No references cited.

